There has been known a conventional method of covering, with a conductive film, the surface of a sealing resin for sealing a semiconductor chip in order to impart a shielding function to a semiconductor package including the semiconductor chip mounted on an interposer substrate. There has also been developed a technique of implementing a module including an antenna by forcing apertures that extend to a conductive portion of an interposer substrate from a main face portion (a face facing a component mounting face of the interposer substrate) to a side face portion (a face facing a side face of the interposer substrate) of a conductive film for shielding, and by using the apertures serving as a slot antenna.
In a case of forming apertures from a conductive film to a conductive portion of an interposer substrate to provide a slot antenna, the aperture in the conductive film and the aperture in the conductive portion of the interposer substrate are formed in separate processes. The aperture in the conductive portion of the interposer substrate is generally formed at the same time as when a pattern such as a wiring pattern is formed on the conductive portion. On the interposer substrate to which a wiring pattern or an aperture has been formed, a component such as a semiconductor chip is mounted, which is then sealed with a sealing resin and covered with a conductive film. The conductive film is then cut with, for example, a laser processing apparatus or an end milling apparatus to form an aperture in the conductive film.
The width of the apertures composing a slot antenna is very small such as approximately 0.1 mm. Thus, it is difficult to form the aperture in the conductive film by correctly aligning the aperture in the conductive film with the aperture in the conductive portion of the interposer substrate that has been formed in advance. If the apertures are discontinuous from each other due to misalignment in the forming, antenna characteristics of the slot antenna deteriorate. In order to provide robustness against such misalignment, the widths of the apertures may be increased. In this case, however, the aperture area on the conductive film increases, and thus shielding performance of the conductive film is degraded.